Here's how GPT works: "For each object in your problem, you break it into parts and ask two questions," explains McCaffrey, who is now a post-doctoral fellow in UMass's engineering department.
"1. Can it be broken down further? and 2. -- this is the one that's been overlooked -- Does my description of the part imply a use?" So you're given two steel rings and told to make a figure-8 out of them. Your tools? A candle and a match. Melted wax is sticky, but the wax isn't strong enough to hold the rings together. What about the other part of the candle? The wick. The word implies a use: Wicks are set afire to give light. "That tends to hinder people's ability to think of alternative uses for this part," says McCaffrey. Think of the wick more generically as a piece of string and the string as strands of cotton and you're liberated. Now you can remove the wick and tie the two rings together. Or, if you like, shred the string and make a wig for your hamster.

The lambda calculus, and the closely related theory of combinators, are important in the foundations of mathematics, logic and computer science. This paper provides an informal and entertaining introduction by means of an animated graphical notation.